I can feel you, I face this problem everytime I play. These gang players really are a problem and they turn players off from server. They abuse server rules in such way that if you breath at them, they have rights to have revenge on you, they will come after the same cops after they spawn over and over again. This is nothing but cophunt within the rules. When you attack a vehicle with 4 players in it, this means that 4 players can have revenge on you. Two vehicles = 8 players. You will have to die 8 times and if you resist and shoot back, this will never end. Changing to civilian won't help, negotiations won't help, admins won't help, nothing will help, all you can do is simply leave server.
This complain surely will be denied, but I ask managment to reconsider the rules, otherwise soon server will only be left with same toxic players, we already seem to loose players for some reason, it might be this. A simple and nice solution might be this - if a player is killed by any other player, every revenge seeker who was close enough and assisted with damage completes their revenge and can no longer come after same player to have revenge - this is done, your prey is killed and you contributed in it, why come again after same poor cop in the same group of 4+ players?